Method and apparatus for crimping filaments



April 16, 1968 F. L. STOLLER 3,377,673

METHOD AND APPARATUS FOR CRIMPING FILAMENTS Filed Dec. 27, 1965 YARN RELAXER SIGNAL GENERATOR SERVO AMPLIFIER FIG.

l8 l {"I'I'l Al GENERATOR sERvo AMPLIFIER g 3 WWW roe F. L. STOLLER ATTORNEYS United States Patent 3,377,673 METHOD AND APPARATUS FOR CRIMPING FILAMENTS Frederick L. Stoller, Bartlesville, Okla, assignor to Phillips Petroleum Company, a corporation of Delaware Filed Dec. 27, 1965, Ser. No. 516,581 14 Claims. (Cl. 281) ABSTRACT OF THE DISCLOSURE In a vibratory crimping method, the vibratory energy which is applied to filaments to obtain crimping is modulated in a predetermined, ultimately random pattern to impart a nonuniform, irregular crimp to the filament.

This invention relates to methods of and apparatus for crimping filaments. In one aspect, this invention re lates to methods of and apparatus for employing vibratory energy to crimp synthetic filaments. In another aspect, this invention relates to the modulation of the vibratory energy in a filament crimping operation to control the degree and regularity of the crimp imparted to the filaments.

Synthetic filaments of thermoplastic materials such as polyamides, polyvinyls, polyolefins, and the like can be texturized to increase their bulkiness by imparting a multitude of crimps to the individual filaments. This can be accomplished by subjecting the filaments to the vibrations emanating from a source of vibratory energy such as an electrical transducer or the like. The prior art techniques for crimping filaments in this manner are unsatisfactory because there is no method available for controlling the degree and regularity of the crimp in the filaments. It frequently happens that filaments texturized in this manner have a crimp which is uniform or regular. Yarns fashioned from filaments having a uniform crimp have a low degree of bulk and fiufiiness because the individual filaments tend to line up in phase and become closely packed. The appearance of a final product prepared by a yarn of this type is not completely satisfactory because of the presence of lines on the surface of the final product transverse to the direction of the filaments. These lines. apparently result from the filaments becoming lined up with their crimps in phase.

According to this invention, these and other disadvantages of the prior art methods and apparatus for texturizing synthetic filaments by vibratory energy are overcome by modulating the vibrations to control the degree and regularity of the crimp imparted to the filaments. In general, this result can be obtained by modulating the frequency and/ or the amplitude of the vibrations at random or according to a predetermined pattern or condition.

In one embodiment of the invention, the magnitude and frequency of the crimps in a filament or in a group of filaments such as a yarn is controlled by modulating both the frequency and the amplitude of the vibrations in response to a predetermined pattern which, in the ultimate, is desirably random in nature. In a modification of this embodiment of the invention, only the magnitude of the crimp in the filaments is varied in response to a predetermined pattern, desirably random in nature. In this modification, the frequency of the vibrations and hence the frequency of the crimps in the filaments is not varied and thus remains substantially constant. In another modification of this embodiment of the invention, the frequency of the vibrations and hence the frequency of the crimps in the filaments is varied according to a predetermined pattern which is desirably random in nature, and the amplitude of the vibrations and hence the magnitude of the crimp in the filaments is maintained 3,377,673 Patented Apr. 16, 1968 substantially constant. In this latter modification, the filaments will have crimps which are substantially uniform in magnitude but which are nonuniform in frequency along the length of the filaments. In both modifications of this embodiment, the magnitude or the frequency of the crimps in the filaments is completely irregular and nonuniform because the crimps are imparted desirably at random, thus providing filaments which can be plied into a yarn which will retain its bulkiness.

In another embodiment of the invention, the magni tude and frequency of the crimp in a filament or in a group of filaments such as a yarn is controlled in response to the rate of travel or speed of the filaments as they travel over the edge of the means providing the vibratory energy to crimp the filaments. This condition for modulating the crimp is particularly suited for crimping filaments which travel at varying speeds such as could occur when the texturizing or crimping treatment operates in conjunction with a filament or yarn drawing operation. In a modification of this embodiment of the invention, nonuniform or irregular crimped filaments can be produced by varying the amplitude of the vibrations in response to a predetermined pattern, preferably random in nature, and the frequency of the crimps in response to the rate of travel of the filaments as they come in contact with the vibration means. As hereinbefore indicated, this modification of the invention is particularly suited for producing filaments having crimps of randomly varying magnitude and of a frequency which remains substantially constant even though the yarn speed changes arbitrarily. Thus, filaments with a particular constant crimp density which will not pack together can be produced. In another modification of this embodiment of the invention, the magnitude of the crimps can be controlled in response to a predetermined pattern, preferably random in nature, and the frequency of the crimps per unit length of filament can be modulated Within certain limits by suitable pulsating means responsive to the rate of travel of the filaments.

Accordingly, it is an object of this invention to provide an improved method and apparatus for crimping synthetic filaments.

Another object of this invention is to provide a method and apparatus for providing synthetic filaments with a nonuniform or irregular crimp.

A further object of this invention is to provide a method andapparatus for producing a nonuniform crimped filament with a substantially constant number of crimps per unit length.

Still another object of this invention is to provide a method and apparatus for controlling the magnitude and/ or the frequency of the crimps imparted to a synthetic filament in response to the rate of travel of the filaments.

A still further object of this invention is to provide a method and apparatus for modulating the amplitude and/ or the frequency of the crimps imparted to a synthetic filament to provide a filament having nonuniform or irregular crimp.

These and other objects of the invention will become apparent to one skilled in the art after studying the following detailed description, the appended claims, and the accompanying drawings wherein:

FIGURE 1 is a schematic illustration of an apparatus including a modulating means for controlling the magnitude and frequency of the filament crimps in accordance with one embodiment of the invention; and

FIGURE 2 is a schematic illustration of an apparatus including a modulating means for controlling the mag nitude and frequency of the crimps in a synthetic filament in accordance with another embodiment of the invention.

Referring now to the drawings, wherein like reference numerals are used to denote like elements, the invention will be described in more detail. Many pulleys, controls, stretchers, rolls, heaters, and the like, not necessary in explaining the invention to one skilled in the art, have been omitted from the drawings for the sake of clarity.

Referring to FIGURE 1, a multitude of thermoplastic filaments in the form of a yarn 1 is passed by suitable drawing means (not shown) between a pair of directional rolls 2, in contact with a suitable vibration means 3, and between a second pair of directional rolls 4. Although the invention will be described in connection with texturizing or crimping a yarn, it is within the spirit and scope of the invention to texturize monofilaments if desired. A yarn relaxer 6 in the form of a heated chamber into which steam can optionally be passed can 'be used to set the crimp in the filaments. It is generally preferred that the crimping edge of the head 8 be positioned oblique to the direction of travel of the yarn 1 to prevent any chance of imparting similar crimps to the several filaments across the yarn.

The vibration means 3 can be any vibrator capable of emitting vibratory energy such as an electrically energized vibrator or an electrical transducer in the form of a piezoelectric member such as a crystal of barium titanate or a laminated plate such as a magnetostrictive member of laminated nickel and other alloy. As illustrated, the vibration 'means 3 includes a magnet 7 which can be of the permanent or electromagnet type and a head 8 connected by a bellows member 9.

A signal generator 11 is connected by electrical conduits 12 and 13 to the actuating coil of vibration means 3 in a manner which will cause the head 8 to vibrate in response to a signal from generator 11. A signal generator which can be used for this purpose is the type 1304-B beat-frequency audio generator illustrated at page 106 in catalog R of the General Radio Company, West Concord, Massachusetts. Any suitable signal generator which will establish a signal which can be made to vary in frequency and/or amplitude in response to a predetermined pattern at random or other condition can be employed in the practice of this invention.

A servo-motor 15 is operatively connected to the signal generator 11 in a manner which will allow selection, modulation, or tuning of the amplitude or the frequency of the generators output in response to a predetermined pattern, preferably at random, obtained from a multipoint stepping switch 14 through the medium of a voltagebalancing or potentiometer circuit including a servo-amplifier 16, a potentiometer 17, and a power supply 18.

In operating according to the embodiment of the invention illustrated by FIGURE 1, the potentiometer circuit functions to select, by the position of potentiometer 17, that voltage from power supply 18 which balances the voltage applied from switch 14, or another signal source. The servo (differential) amplifier 16 in the potentiometer circuit amplifies any uulbalance in electrical potentials which drives motor 15 to rotate the shaft of potentiometer 17 to its balanced position. Also connected to the shaft of motor 15 is the amplitude or frequency adjustment shaft of generator 11 whereby the amplitude or the frequency of generator 11 is varied in accordane with the voltage signal from switch 14. Contact arm 19 is rotated or otherwise moved by motor 21 among positions indicated by the letters A through H at which different potentials are available as the signal source. In practice, switch 14 is scanned by arm-contactor 19 serially A through H, and is shown in the voltage source-contact sequence relationship of FIGURE 1 only for the sake of simplicity. When the frequency of the crimps is to be varied per unit length, the servo-motor 15 is connected to the frequency modulating shaft of the signal generator 11 to vary the frequency (cycles per second) of the signal to the vibration means 3 in re sponse to the predetermined pattern obtained by balancing the voltage from the stepping switch 14 with the servo-selected voltage in the potentiometer circuit.

In accordance with a modification of this embodiment of the invention, the servo-motor 15 can be connected to the amplitude modulating shaft of the signal generator, thereby causing the amplitude or magnitude of the crimps in the yarn 1 to be varied in response to the random pattern of the stepping switch 14 and the potentiometer circuit. In this modification, the frequency of the vibrations is unaltered and thus remains substantially constant.

It is evident that both the amplitude and the frequency of the vibrations in the vibrating means 3 can be modulated by employing separate servo-driven voltage-balancing systems, one of which can be used to control the amplitude and the other of which can be used to control the frequency of the crimps according to predetermined patterns, preferably at random.

In another embodiment of the invention, illustrated by FIGURE 2 of the drawing, the rate of travel or speed of the yarn in passing over the vibrator head 8 can be used as a condition for controlling the amplitude of the vibrations. In a modification of this embodiment, the speed of the yarn can be used for controlling the amplitude or magnitude of the vibrations and the frequency of the vibrations can be controlled, preferably at random, Within certain limits by suitable pulsating means. In this embodiment of the invention, a speed pickup 22 operatively .connected to one of the directional rolls 2 and a generator-transducer 23 will serve to establish a voltage in response to the rate of travel or speed of the yarn. This voltage can be used to modulate the frequency and/ or the amplitude of the vibrating head 8 through the medium of the voltage-balancing circuit including the servo-amplifier 16, the potentiometer 17, the power supply 18, the servo-motor 15, and the signal generator 11.

In a modification of this embodiment of the invention, the servo-motor 15 can be connected to the signal generator 11 in a manner which will allow the amplitude of the vibrations to be varied in accordance with a predetermined pattern, preferably at random, by means of the stepping switch 14 illustrated in FIGURE 1. The frequency of the vibrations can be modulated by means of a separate voltage-balancing circuit including a servo-amplifier, servo-motor, and potentiometer, all of which is operatively connected to the signal generator 11 in a manner which will allow the frequency of the vibrations to be modulated in response but not necessarily in direct proportion to the rate of travel of the yarn 1 by balancing the voltage from generator 23 with the voltage in the potentiometer circuit. This will result in the formation of a textured yarn having a substantially constant frequency of crimps per unit length which vary in magnitude substantially at random.

With respect to the rate of change of the voltage from the stepping switch 14, the dwell time of the contact arm 19 can be regulated within wide limits by controlling the speed of motor 21. Depending upon the rate of travel of yarn 1 over the vibrator head 8, the rate of change of the voltage through the stepping switch 14 can be selected to produce varying crimp intervals as desired. Generally, it is preferred to change the position of the contact arm 19 and hence the frequency and/or the amplitude of the vibrations about every second or less. If the yarn is traveling at unusually high rates of speed, the frequency and/ or the amplitude of the vibrations can be changed as often as every 0.1 second. The one second and 0.1 second periods between change are merely suggestive and must not be construed to impose limitations on the invention. Thus, it is possible to practice the method of this invention with an apparatus which will impart changes in frequency and/or amplitude every 0.01 or 0.001 second or less. It is also within the scope of the invention to vary the frequency and/or amplitude of the vibrations continuously and at random between wide limits.

Although the frequency of the vibrations can vary from subsonic to sonic and up to and including ultrasonic, it is generally preferred to operate in the ultrasonic ranges.

While the selection of the voltage to be balanced in the potentiometer circuit is accomplished by means of a stepping switch, it is evident that any comparable device for obtaining difierent voltages at random or in a timed sequence can be substituted if desired. It is also within the spirit and scope of this invention to employ any type of vibrator which will impart crimps to the filaments of the yarn. It is also evident that the potentiometer circuit and voltage-balancing circuit is only one of several different ways in which the amplitude and frequency of the vibrator can be modulated.

Although the invention has been described in considerable detail, it must be understood that such detail is for that purpose only and that many variations and modifications can be made without departing from the spirit and scope of the invention.

I claim:

1. In a method of crimping a synthetic filament including the step of applying vibratory energy to said filament to form a crimp therein, the improvement comprising modulating said vibratory energy in a predetermined ultimately random pattern to control the degree and regularity of the crimp imparted to said filament to obtain a nonuniform, irregular crimp.

2. A method according to claim 1 wherein said filament is passed in contact with means for applying said vibratory energy and wherein said vibratory energy is modulated in response to the travel of said filament.

3. The method of claim 2 wherein the frequency of said vibratory energy is modulated.

4. The method of claim 2 wherein the amplitude of said vibratory energy is modulated.

5. The method of claim 2 wherein both the frequency and amplitude of said vibratory energy are modulated.

6. A method according to claim 1 wherein the amplitude of said vibratory energy is modulated.

7. A method according to claim 1 wherein the frequency of said vibratory energy is modulated.

8. A method according to claim 1 wherein said vibratory energy is modulated at random.

9. A method according to claim 1 wherein said vibratory energy is modulated by establishing a first signal at random; balancing said first signal with a substantially constant like signal; establishing a second signal responsive to the balancing of said first signal with said substantially constant like signal; and modulating said vibratory energy in response to said second signal.

10. A method according to claim 1 wherein said filament is passed in contact with the edge of a suitable vibration means for applying said vibratory energy and wherein the edge of the vibration means is oblique to the direction of travel of said filament.

11. The method of claim 1 including modulating both the frequency and amplitude of said vibratory energy.

12. Apparatus for crimping filaments comprising vibration means for imparting vibrations to said filaments to impart a crimp therein; means for establishing a first signal at random; means for balancing said first signal with a substantially constant like signal; a signal generator connected to said means for balancing said first signal with said like signal for establishing a second signal in response to the magnitude of said first signal and said like signal; and means connected to said vibration means and said signal generator to transmit said second signal to said vibration means to modulate the vibrations therefrom in response to said first signal.

13. Apparatus according to claim 12 wherein said means for establishing said first signal includes a stepping switch adapted to establish voltages of randomly varying magnitudes.

14. Apparatus according to claim 12 wherein said means for establishing said first signal includes a generator operatively connected to said filaments to establish a voltage in response to the rate of travel of said filaments in contact with said vibration means.

References Cited UNITED STATES PATENTS 2,897,426 7/1959 Hotine 31820.745 2,943,377 7/1960 Freiberger 28-1 2,945,282 7/1960 Freiberger 281 3,076,128 1/1963 Toski et al 318-20.745 X 3,304,593 2/1967 Burklund 28-72 LOUIS K. RIMRODT, Primary Examiner. 

